1. Field of the Invention
The invention relates generally to a sodium storage and injection system for delivering a fine spray of high purity sodium to a reactor, and more particularly to a storage and injection system for liquefied sodium having a capability of functioning in start-up, shut-down, normal operating and emergency modes for injecting liquefied sodium into an arc furnace for reducing silicon tetrachloride in the production of solar grade silicon.
As disclosed in U.S. application Ser. No. 873,993, filed Jan. 31, 1978, incorporated herein by reference thereto, substantial attention currently is being given to the use of silicon solar cells in converting solar energy directly to electrical energy. As is well known, silicon solar cells are characterized by photovoltaic capabilities and heretofore have been employed extensively in the aerospace industry, particularly in the exploration of celestial space. Unfortunately, extensive use of solar cells for converting solar energy to electrical energy in a terrestrial environment has been impaired, in part, by the relatively insufficient supply of solar grade silicon.
With a view to enhancing usage of solar cells in the production of energy, efforts are being made to increase the supply of solar grade silicon. Such has led to a suggestion of various production techniques including a process wherein solar grade silicon is produced through a reduction of silicon tetrachloride using sodium in the presence of heat above the melting point of silicon. This technique requires that silicon tetrachloride of a relatively high purity be injected into an arc furnace, or similar reactor, simultaneously with the reductant sodium. Any system employed in performing this process must possess a production capacity sufficient to satisfy economic requirements. This, in turn, requires that accurate control be maintained over the delivery of the sodium and its injection into the reactor.
It is, therefore, the general purpose of the instant invention to provide a unique system for delivering and injecting a controlled spray of high purity sodium under pressure into a chemical reactor.